The present invention relates to hermetic assemblies and more particularly to a hermetic assembly arrangement which can be associated with electrical connection openings of a walled housing for large motor units.
It is well known in the art to provide a terminal assembly which incorporates a current carrying electrically connected terminal pin which extends in sealed relation through a cup-shaped body. The cup-shaped body, in turn, is fixedly mounted in sealed relation in a housing wall opening, the outer segment of the pin being connected to an electrical power source and the inner segment of the pin being hermetically confined in the housing and conductively connected to an appropriate hermetically sealed motor unit in the housing. Such a hermetic terminal assembly arrangement can be found in a number of U.S. patents issued to Benjamin Bowsky et al, including U.S. Pat. No. 4,584,433, issued on Apr. 22, 1966, the general arrangement being particularly adapted to hermetically sealed housings for comparatively low horse-power rated compressor units (for example, one horse-power) and, as above noted, each of the terminal assemblies is permanently fixed in sealed position with respect to the housing with which it is associated.
In those instances where compressor units have been much larger and have had a comparatively much higher horse-power rating (for example, ninety horse power) it also is known to provide current electrically connected terminal pins each of which can be threaded adjacent at least at one extremity and bolt head configured at the other or threaded adjacent both extremities to extend through opposed faces of an annular compressible seal usually of rubber. The compressible annular seal is sized to snugly engage in an opening in the wall of the housing for the compressor with the outer surrounding peripheral surface of the seal abutting the inner periphery of the wall opening and the inner periphery abutting the peripheral surface of the conducting pin. A threaded nut, or a pair of nuts, depending on the nature of the threaded type of pin utilized, engages with the pin threads to longitudinally urge separate annular insulated members against opposed faces of the annular compressible seal to radially expand the same, thus providing tightened sealing engagement between the pin and housing wall opening. Such past arrangements conventionally have required fabricated insulation panels on opposite sides of the wall through which the pin extremities pass to further insulate the pins, the panel requiring a removal of all tightening nuts to gain full access to one pin.
It has been recognized that this past adjustable arrangement not only is comparatively expensive in manufacture and assembly, but that the compressible expansible seal leads to sealing problems due to thermal changes and compressible material distortions which might occur. In addition, it has been recognized that problems of accessibility and effective sealing during assembly can occur since uniform pressure along both faces of the compressible seal is required to provide uniform radial expansion of the compressible seal for effective sealing along both the peripheral wall of the opening and the peripheral surface of the pin.
In accordance with the present invention, a unique terminal assembly arrangement resolves these recognized problems, providing a self-contained pin assembly which utilizes a minimum of parts, which can be economically and readily manufactured and which can be assembled for quick installation and removal in the wall openings of a housing for hermetic sealing therewith, without requiring fabricated insulation panels and the concomitant requirement of a removal of all associated tightening nuts to gain access to one pin. In addition, each of the unique and novel terminal assembly arrangement can be inserted as a complete unit including glass to metal seals within the opening of a housing in a minimum of time and with a minimum of steps to provide a positive, uniform hermetic seal with the wall housing panel that is operational over long periods of time for broad thermal ranges.
Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.